Abstract: A method of depositing a conductive material is described. The method includes: providing a plate selected from anode plates, cathode plates, bipolar plates, or combinations thereof, wherein the plate includes gas flow channels; providing a diffusion media in contact with the gas flow channel side of the plate to form an assembly; introducing a gaseous precursor of the conductive material into the assembly using a chemical vapor infiltration process; infiltrating the gaseous precursor into the diffusion media and gas flow channels of the plates; and depositing a coating of the conductive material on the diffusion media, the gas flow channels of the plate, or both. An assembly having a CVI conductive coating and a fuel cell incorporating the diffusion media having the CVI conductive coating are also described.

Abstract: Methods of making a substantially crack-free electrode layer are described. The methods include depositing an electrode ink on a substrate; placing a solid polymer film on a surface of the wet electrode ink; drying the electrode ink; and removing the solid polymer film from the surface of the dry electrode ink to form the substantially crack-free electrode layer on the substrate.

Abstract: One exemplary embodiment includes a fuel cell comprising a polymer electrolyte membrane sandwiched between an anode and a cathode, a gas diffusion layer disposed over each of the cathode and the anode, a gas flow distributor layer disposed over the gas diffusion layer on both the anode and cathode sides, and optionally a coolant plate disposed over the gas flow distributor layer. The thermal resistance of the combined gas diffusion layer and gas flow distributor layer on the anode and/or cathode side is sufficient to allow the cathode catalyst layer to operate at an elevated temperature to effectively evaporate water produced at the cathode.

Abstract: A fuel cell comprises a cathode gas diffusion layer, a cathode catalyst layer, an anode gas diffusion layer, an anode catalyst layer and an electrolyte. The diffusion resistance of the anode gas diffusion layer when operated with anode fuel is higher than the diffusion resistance of the cathode gas diffusion layer. The anode gas diffusion layer may comprise filler particles having in-plane platelet geometries and be made of lower cost materials and manufacturing processes than currently available commercial carbon fiber substrates. The diffusion resistance difference between the anode gas diffusion layer and the cathode gas diffusion layer may allow for passive water balance control.

Abstract: A diffusion medium for use in a PEM fuel cell including a porous spacer layer disposed between a plurality of perforated layers having variable size and frequency of perforation patterns, each perforated layer having a microporous layer formed thereon, wherein the diffusion medium is adapted to optimize water management in and performance of the fuel cell.

Abstract: Methods of making a substantially crack-free electrode layer are described. The methods include depositing an electrode ink on a substrate; placing a solid polymer film on a surface of the wet electrode ink; drying the electrode ink; and removing the solid polymer film from the surface of the dry electrode ink to form the substantially crack-free electrode layer on the substrate.

Abstract: One exemplary embodiment includes a fuel cell comprising a polymer electrolyte membrane sandwiched between an anode and a cathode, a gas diffusion layer disposed over each of the cathode and the anode, a gas flow distributor layer disposed over the gas diffusion layer on both the anode and cathode sides, and optionally a coolant plate disposed over the gas flow distributor layer. The thermal resistance of the combined gas diffusion layer and gas flow distributor layer on the anode and/or cathode side is sufficient to allow the cathode catalyst layer to operate at an elevated temperature to effectively evaporate water produced at the cathode.

Abstract: A diffusion medium for use in a PEM fuel cell including a porous spacer layer disposed between a plurality of perforated layers having variable size and frequency of perforation patterns, each perforated layer having a microporous layer formed thereon, wherein the diffusion medium is adapted to optimize water management in and performance of the fuel cell.

Abstract: A method of depositing a conductive material is described. The method includes: providing a plate selected from anode plates, cathode plates, bipolar plates, or combinations thereof, wherein the plate includes gas flow channels; providing a diffusion media in contact with the gas flow channel side of the plate to form an assembly; introducing a gaseous precursor of the conductive material into the assembly using a chemical vapor infiltration process; infiltrating the gaseous precursor into the diffusion media and gas flow channels of the plates; and depositing a coating of the conductive material on the diffusion media, the gas flow channels of the plate, or both. An assembly having a CVI conductive coating and a fuel cell incorporating the diffusion media having the CVI conductive coating are also described.

Abstract: A fuel cell includes a first electrically conductive plate and a first gas diffusion layer. The first gas diffusion layer is disposed over the first electrically conductive plate. Characteristically, the first gas diffusion layer comprises a first fibrous sheet having fibers coated with an electrically conductive layer. A first catalyst layer is disposed over the first gas diffusion layer and an ion conducting membrane is disposed over the first catalyst layer. The fuel cell also includes a second catalyst layer disposed over the ion conducting membrane with a second gas diffusion layer disposed over the second catalyst layer. A second electrically conductive plate is disposed over the second gas diffusion layer. Methods for forming the gas diffusion layers and the fuel cell are also provided.

Abstract: A gas diffusion layer for use in fuel cells comprises a fiber and non-fiber material in a ratio such that the water vapor diffusion transport resistance is greater than 0.8 s/cm measured at 80 C and 150 kPa absolute gas pressure when the gas diffusion layer has a thickness less than or equal to 300 microns. Another gas diffusion layer comprises a fiber and non-fiber material in a ratio such that the water vapor diffusion transport resistance is lower than 0.4 s/cm measured at 80 C and 150 kPa absolute gas pressure when the gas diffusion layer has a thickness greater than or equal to 100 microns. Fuel cells incorporating the gas diffusion layers are also provided.

Abstract: A gas diffusion layer for use in fuel cells includes a gas permeable diffusion structure and a microporous layer. The microporous layer incorporates a plurality of particles of anisotropic shape, simultaneously reducing the porosity of the microporous layer and increasing the tortuosity for gas transporting through the microporous layer. The anisotropic particles in the microporous layer are present in a first amount such that the gas diffusion layer has an increased gas transport resistance.